Cavy meaning : A tailless rodent of the family Caviidae and the genus Cavia, with short ears and larger than a hamster; the species Cavia porcellus is often kept as a pet. A rodent of any of several species within the family Caviidae. A living experimental subject. A professional company director, without time or real qualifications for the duties. A midshipman in the East India service; (by extension) a low-skilled or non-proficient seaman.